It has been recently established that causality, crossing and unitarity constrain Wilson coefficients both from above and from below [1]}, [2]}, [3]}, [4]}. In the space of couplings formed by weakly-coupled theories it is thus natural to talk about the theory island, namely the region spanned by known perturbative UV completions of gravity. By definition we have
\(\text{Theory island} \subseteq \text{EFThedron} ,\) 
